The present invention relates to improvements to cutting apparatus for cutting sheet materials, particularly but not exclusively of the type for use with a rolled supply of floor covering material.
Devices used for cutting carpet, vinyl flooring, and other floor covering materials are known. These devices can be as simple as a rack for supporting a roll of floor covering material adjacent a cutting surface such as a floor or table top or may be complex machines. In the simple case where a rack and cutting surface are used the floor covering material is dispensed from the rack onto a cutting surface where it is cut by an individual with a knife. After cutting the floor covering material is manually re-rolled. One disadvantage of this method is that large areas are required to lay out the floor covering material during cutting. A second disadvantage is that if the floor covering material is cut on a floor the floor covering material can be damaged by contact with materials on the floor.
More complex apparatus for performing this task are also known. One example is shown in U.S. Pat. No. 4,809,921 issued Mar. 4th 1889 of Willie Dueck who is the father of the present inventor. This includes a cradle or rack for supporting the roll of floor covering material to be dispensed, a table top across which the floor covering material is drawn, and a cradle for automatically re-rolling the floor covering material. These components are generally mounted on a frame to keep them raised above the floor at an appropriate height for working. A knife blade arranged for travelling across the table top is usually employed to cut the floor covering material. The knife blade is usually mounted at a fixed angle to the table and moves along a slot running laterally across the table through which the knife blade projects.
Also in U.S. Pat. No. 5,944,279 issued Aug. 31st 1999 to the present inventor is disclosed an improved cutter of this general type where the sheet material is guided and controlled by electric xe2x80x9ceyesxe2x80x9d which detect the position of the edges of the material. These can primarily be used to calibrate the measuring roller to ensure greater accuracy in the measurement.
It is one object of the present invention to provide a yet further improved cutter for rolled material such as floor covering material.
According to the present invention there is provided an apparatus for cutting a length of sheet material from a supply of the sheet material comprising:
a carriage;
an unrolling device on the carriage for unrolling a supply roll of the sheet material, the unrolling device being driven such that a front edge of the roll is supplied from the roll;
a table surface on the carriage for receiving the sheet from the unrolling cradle such that the sheet passes longitudinally across the table when fed from the unrolling device;
a sheet driving roller on the carriage for driving the sheet from the unrolling device across the table;
a metering wheel on the carriage arranged to roll on the sheet as it passes from the unrolling cradle and across the table surface for measuring a length of the sheet supplied from the unrolling device;
a de-activation detector responsive to de-activation of the metering wheel;
a cutting knife mounted at the table surface and movable transversely across the table surface to slit the sheet at a position along the sheet to form a cut portion of the sheet having a required length;
a re-rolling cradle on the carriage for receiving the front edge and the cut portion and driven to roll the cut portion from the front edge into a roll for supply of the cut portion;
a material detector mounted in a path of movement of the sheet material from the unrolling device to the re-rolling cradle for detecting passage of a front edge of the sheet material and the presence of the sheet material;
a printer for printing a label recording a length of the sheet material as measured by the metering wheel;
and a control unit responsive to the detection of the front edge by the material detector to commence measuring of the length by the metering wheel to provide a measured length of the material;
the control unit being responsive to the de-activation sensor and arranged to prevent printing of a label recording the length in the event that the de-activation sensor detects a de-activation during measuring of the length.
Preferably the material detector comprises an electric eye.
Preferably the material detector is mounted at the table.
Preferably the material detectors is mounted upstream of and adjacent to the cutting knife.
Preferably the metering wheel is mounted closely adjacent to the cutting knife.
Preferably the metering wheel is mounted immediately prior to the cutting knife.
Preferably the metering wheel is mounted so as to contact one surface of the sheet and there is provided a second contacting wheel mounted to contact an opposed surface of the sheet.
Preferably the de-activation sensor is arranged to detect separation of the metering wheel and the contacting wheel.
Preferably the contacting wheel is mounted on a lever above the table and is movable on the lever to separate the contacting wheel and the measuring wheel.
Preferably the de-activation sensor and the material sensor are mounted on the lever.
Preferably the printer is arranged to generate a machine readable bar code containing information defining the sheet material and the length.
Preferably the control unit is arranged to drive the unrolling device and the sheet driving roller to a predetermined length as measure by the measuring wheel.
Preferably the control unit is arranged to slow a speed of drive of the unrolling device and the sheet driving roller as the length is approached.
Preferably the carriage is arranged to be located adjacent a horizontal roll of the sheet material carried on a carrousel and wherein the unrolling device comprises an elongate horizontal drive roller extending along the roll parallel to an axis of the roll and movable into contact with the roll while the roll remains on the carrousel.
Preferably the carriage is mounted on rails for movement in a direction parallel to the axis of the roll.
Preferably the rive roller is arranged to be driven by the control unit in a reverse direction for re-rolling the sheet material onto the roll on the carrousel.
According to a second aspect of the invention there is provided an apparatus for cutting a length of sheet material from a supply of the sheet material comprising:
a carriage;
an unrolling device on the carriage for unrolling a supply roll of the sheet material, the unrolling device being driven such that a front edge of the roll is supplied from the roll;
a table surface on the carriage for receiving the sheet from the unrolling cradle such that the sheet passes longitudinally across the table when fed from the unrolling device;
a sheet driving roller on the carriage for driving the sheet from the unrolling device across the table;
a metering wheel on the carriage arranged to roll on the sheet as it passes from the unrolling cradle and across the table surface for measuring a length of the sheet supplied from the unrolling device;
a de-activation detector responsive to de-activation of the metering wheel;
a cutting knife mounted at the table surface and movable transversely across the table surface to slit the sheet at a position along the sheet to form a cut portion of the sheet having a required length;
a re-rolling cradle on the carriage for receiving the front edge and the cut portion and driven to roll the cut portion from the front edge into a roll for supply of the cut portion;
a material detector mounted in a path of movement of the sheet material from the unrolling device to the re-rolling cradle for detecting passage of a front edge of the sheet material and the presence of the sheet material;
and a control unit for driving the unrolling device and the sheet driving roller;
wherein the carriage is arranged to be located adjacent a horizontal roll of the sheet material carried on a carrousel and wherein the unrolling device comprises an elongate horizontal drive roller extending along the roll parallel to an axis of the roll and movable into contact with the roll while the roll remains on the carrousel.